US spokesman Master Sergeant Robert Cargie said soldiers from the 4th Infantry Division were staking out a house in Tikrit's Qadisiya district, looking for suspects in earlier rocket attacks, when they were shot at with automatic weapons.

The US soldiers returned fire and threw a hand grenade, killing one man and injuring two others.

"At one point after the wounded were taken care of, it was learned that the attacker who was killed was an Iraqi police major," Cargie said.

A senior official in Khalaf's tribe, Sheikh Hamid Iqab al-Dulaimi, said Khalaf had just reached home when US troops opened fire.

"He was just coming home from his duty," he said. "US troops had mounted some kind of ambush in the area, I do not know why. He got out of his car and was surprised when they started shooting.

"His brother went outside, and they shot at him too. He was wounded. They took him and left, and later they came back and took off (Khalaf's) clothes and left him naked in the street."

Cargie said US troops arrested two other men and confiscated two AK-47 assault rifles, he said.

Patrol hit

Also on Sunday, a US patrol was hit by a homemade bomb on the main expressway that cuts through the Iraqi capital, north to south, police said.

Later on the same day, Prince Charles paid a surprise morale-boosting visit to British troops in Iraq, and spoke to local officials about their concerns over the country's future.

Amid heightened security, Charles arrived on a Chinook helicopter at a British base that was one of Saddam Hussein's lavish palaces, shaking hands with soldiers and officials of the US-led civil administration.

During the nearly six-hour trip, he listened to prominent Iraqi officials discuss a wide range of political and economic problems plaguing postwar Iraq.

At one stage, gunshots rang out from a neighbourhood near the base in the southern port city of Basra, underscoring Iraq's precarious security situation.

It was a rare visit by a British royal to the country that won independence from Britain in 1932. Prime Minister Tony Blair visited Basra last month.